My first grow was a soil grow using the Same OceanForest and the Fox Farms Trio.. I started to have a CalMag issue early on, so I went ahead and started using the CalMag, and solved the issue.
I then moved to Hydro, and NEEDED CalMag, I am now running Hempy Buckets and started using the Lucas Formula, so CalMag was not supposed to be necessary, but guess what, I am still using CalMag, cause as long as you are feeding your plants a balanced diet, CalMag Deficiency is seems to be the MOST COMMON Deficiency, so just accept it, and Stock Up on the Botanicare CalMag + or whatever CalMag Supplement you want to use.